Microbiologists identify 'drunken stargazing snake' virus

Microbiologists have identified an entirely new class of virus that they believe is responsible
for a mysterious condition that causes bizarre "drunken" behaviour
and eventual death in snakes.

Inclusion
Body Disease (IBD) affects boa constrictors and pythons and
causes them to first regurgitate food. They then display
neurological problems, one of which is "stargazing" -- where the
snake just stares upwards for long periods of time. Following that,
the creatures act drunk and "tie themselves in a knot that they
can't get out of", according to Michael
Buchmeier, a professor of infection diseases at the University
of California. Ultimately, snakes with the disease develop pockets
of foreign material (known as inclusions) within their cells, which
proves fatal.

Buchmeier's team has been investigating an outbreak of IBD in
snakes at the Steinhard
Aquarium in San Francisco. They believe that they have
identified a virus responsible for the common but deadly
condition.

In a study in mBio,
the authors report that the virus represents a whole new class of
arenaviruses that have never been seen before. The disease is
devastating for zoos as it can rapidly affect a large number of
snakes before it is identified. There is currently no treatment for
the disease, so infected snakes must be euthanised.

The research team extracted and sequenced DNA from tissue samples taken from boas and pythons.
In amongst the snake DNA they found a sequence of DNA that belonged
to viruses, specifically members of the arenavirus family.

The authors were able to grow an isolate one of those viruses in
the laboratory. Curiously, it doesn't neatly fall into either of
the two known
categories of arenaviruses -- Old World and New World. The very
fact that the virus was found in snakes was also surprising, since
until now arenaviruses had only ever been found in mammals.

The virus also had a gene that was very closely related to a
gene in the ebola virus. This could help researchers begin to
understand how some dangerous viruses in animals end up swapping
species and infecting humans.

Buchmeier said: "This is one of the most exciting things that
has happened to us in virology in a very long time. The fact that
we have apparently identified a whole new lineage of arenaviruses
that may predate the New and Old World is very exciting."

He credited metagenomic
techniques that examine large samples of DNA for small bits of
information as being particularly powerful when it comes to
identifying new viruses. "Twenty years ago we would have called
this a fishing expedition. It is fishing, but the techniques are so
good and so sensitive that they allow us to determine which new
types are there," he said.